Concrete blocks come in a variety of shapes and sizes. Their colours range from the lightest pink to the darkest charcoal….and everything in between. The common factor with all concrete blocks is they are made of….you guessed it….concrete.
This post touches on concrete blocks that give a bad reputation to the many magnificent block paving driveways in the United Kingdom.
First of all lets look at sunken concrete blocks. Below is an example of a block paving driveway surface that has sunken. Ignore the moss growth and look at the way some blocks have sunken, which in turn has made other blocks lift.
Concrete Blocks – What causes them to sink?
The cause of most sinking problems is a sub base giving way. Contrary to some opinions, it has nothing to do with the blocks themselves and hardly ever to do with the pattern blocks have been laid in.
Sub base installation is the most important part of any driveway installation. Occasionally, sub soil beneath a sub base can give way, but this is highly unlikely especially with the soil types in most regions of the UK.
Flooding may cause underground water to weaken sub soils, but again this is quite exceptional.
Look at the picture below. The sinkage and raised block present real trip hazards that could lead to a sprain, or worse. This is particularly hazardous for both the young and old.
Unfortunately, driveway extensions are another cause of sinking edges along driveways. Scrimping on not laying a suitable sub base is unwise, as a block paving installation like this may collapse at the edges. The driveway extension below shows sinkage along edges and the cause is the poor sub base underneath.
The last example shows a driveway in need of an urgent repair. No attempt has even been made to install a sub base along this front edge! These concrete blocks have just been pushed against the front and are dangerous and look terrible, too.
If there is a temptation to reduce costs by laying an inferior sub base, find another way to save money.
Please contact us if you need a Quality Block Paving Installer